In an article in Cell Systems, a multidisciplinary team at the Wyss Institute for Biologically Inspired Engineering describes an instrument they engineered that can ‘breathe’ in and out, actively smoke regular and electronic cigarettes much like a human, and then deliver the smoke to microfluidic organs-on-chips lined by human lung small airway cells isolated from non-smokers or COPD patients. The integrated smoking system enables a better understanding of smoke-related pathological changes in individual smokers, and could facilitate the discovery of more accurate biomarkers and new therapeutic targets.